Yea Flashcards
How does carbon dioxide enter the plant? (2 mark)
Diffuses from the air into the plant through the stomata
How does water get in the plant?
Water enters the roots from the soil through the root hair cells by osmosis
What is the oxygen used for in plants?
Respiration
It’s released back into the environment
What is the balanced equation for photosynthesis?
6CO2 + 6H2O————-) C6H12O6 + 602
What are the 2 main stages of photosynthesis reactions?
Light dependant and light independent
How to test for starch in photosynthesis
Using forceps ,place the leaf in a beaker of boiling water for a minute to kill it.
Then ,using forceps, place the leaf into a boiling tube of boiling ethanol to remove all chlorophyll.
Then wash the leaf to remove the thanol and soften the leaf and spread it out on a white tile
Add a few drops of iodine solution
If it contains starch it will go from yellow-brown to blue-black
How do you destarch a plant?
Place it in the dark for a minimum of 24 hours
How do you prove chlorophyll is needed in photosynthesis?
Place a destarched leaf in light for several hours.
You then test one of its leaves for starch
How can you prove carbon dioxide is needed for photosynthesis?
Take a destarched plant and place it in a polythene bag.Before you seal the bag add a pot of soda lime.This is a chemical that absorbs Carbon dioxide and water vapour.
Place the plant in sunlight for several hours and then test one of its leaf for the presence of starch.
How can you measure the rate of photosynthesis?
By measuring how much oxygen or glucose a plant makes in a given time.
Glucose is used to produce new cells.so you can also measure the rate of photosynthesis by calculating the increase in biomass in a given time
What is the formula to calculate the rate of photosynthesis?
Rate= 1/t, where t is time for the measurement to occur?
How much carbon dioxide is in the atmosphere? What does this show for photosynthesis?
0.04 percent
This means that CO2 is the most common limiting factor
What is one way you can investigate the rate of photosynthesis?
Using elodea (pondweed)
The volume of oxygen per minute is a measure of the rate of photosynthesis you can measure this by counting the number of bubbles produced per minute
What is the inverse square law?
When you double the distance from the light source the light intensity falls by a factor of four
What is the formula for relative light intensity?
1/distance from the light source *2
